1. Field of the Invention
The present invention relates to a planar rotation mechanism, more particularly to a planar rotation mechanism of supporting device that can be used in situations that when an object to be supported, e.g. a flat panel monitor, is operated with a planar rotation (switch from horizontal to vertical or vice versa), one corner of the lateral end of the object to be supported is firstly and horizontally moved a small distance alongside the bottom end of the object to be supported then is rotated.
2. Description of Related Art
A flat panel monitor, such as a LCD monitor, a LCD TV or a plasma TV, has advantages of light in weight, thin in thickness and no radiation. Therefore, most of CRT TVs are replaced. In order to let a flat panel monitor being uprightly disposed, a connecting unit is served to connect the flat panel monitor to a base seat, and a hinge is provided between the flat panel monitor and the connecting unit, so the flat panel monitor has a function of adjusting viewing angle.
For providing more viewing fashions of a flat panel monitor, the CHINA patent NO. 1244852C granted on Mar. 3, 2006, corresponding to the U.S. Pat. No. 6,822,857, “Monitor improved in a tilting structure” is taken as an example; the monitor includes a monitor main body, and a monitor supporting rack is provided on the back of the monitor main body, a base seat hinge provided on top of a base seat is pivotally connected to a bottom end of a connecting unit, a main hinge is provided on the top end of the connecting unit, and the main hinge is pivotally connected to a main supporting rack, the monitor supporting rack and the main supporting rack are pivotally connected via a pivotal shaft section, so the monitor main body and the monitor supporting rack can be operated with a planar rotation on the main supporting rack via the pivotal shaft section. Because there is a height between the bottom end of the monitor main body and the base seat, if the height is smaller than the distance between one bottom corner of the bottom end of the monitor main body and the pivotal shaft section, when the planar rotation is operated, the bottom corner of the bottom end of the monitor main body will hit against a surface of a desk, and this may cause damage on the monitor main body. For improving such disadvantage, the connecting unit has be to provided with a height adjusting function, so before the planar rotation is operated, the height between the monitor main body and the base seat has to be adjusted to a value larger than the distance between the bottom corner of the bottom end of the monitor main body and the pivotal shaft section, so the monitor main body can be operated with the planar rotation. A flat panel monitor's size is getting larger or has a different spec for the ratio of length and wide, such as 16:9, thus the distance between the bottom corner of the bottom end of the monitor main body and the pivotal shaft section is significantly increased, so the above mentioned planar rotation mechanism is difficult to be adopted.
The US patent publication serial No. 2006/0223596, “Rotating and sliding type mobile communication device”, wherein the communication device is composed by a main body and a sliding member, the main body has a pair of guiding slots, the two guiding slots are respectively provided at two lateral sides of the center of the main body and have different curvatures and lengths. A LCD monitor is provided at the front portion of the sliding member for outputting various video/audio signals, the rear, portion of the sliding member is provided with a pair of coupling convex columns; when the pair of coupling convex columns slides alongside the pair of guiding slots, a vertical status of the sliding member is changed into a horizontal status relative to the main body. In fact, this art is applied on a cell phone, when the planar rotation is operated, the sliding member is upwardly slid along the main body and gradually tilted until the sliding member is positioned, so the sliding member is horizontally disposed on the main body. Because such art is not applied on a monitor, a height between a monitor main body and a base seat can be neglected, and during the rotating and sliding movement, the sliding member is firstly upwardly moved then rotated, there is no horizontal motion involved.
So providing an object to be supported, e.g. a flat panel monitor, with functions that when a planar rotation is operated, a bottom corner of a bottom end thereof will not hit against a surface of a desk, and during the planar rotation the flat panel monitor can be smoothly and stably moved without causing vibration is a task to be overcome.